New York — NEW YORKThe disheveled man looks momentarily confused. He’s wearing a puffy red coat that looks as if it was salvaged from the city dump. “Are you guys cops?” he asks.

He’s been set upon by four Hasidic Jews in the center aisle of House and Home Hardware on Flushing Avenue, a commercial strip that runs through the Hasidic section of Williamsburg in Brooklyn – a neighborhood uncanny for its resemblance to a 19th-century shtetl.

The man’s presence is as misplaced as a Hell’s Angel in Amish country. But it’s not just the grimy clothes that make him unwelcome: His pants are inexplicably torn open, exposing his boxer shorts to the frightened Hasidic patrons he’s been begging for money.

With bushy beards and black yarmulkes, the four Jews entreating the vagabond do so with an air of authority. Their intimidating posture, coupled with the two-way radios that hang from their belts, elicits the man’s question again: “Are you guys cops?”

“Just get out of here,” he’s told, with an expletive thrown in to convey gravity. The man leaves and order is returned to the shop.

The four enforcers may not be members of the New York Police Department, but to the hardware store manager, if they’re not exactly the law, they’re certainly keepers of the peace. They’re members of a volunteer civilian patrol called Shomrim (Hebrew for “watchers”), which, in addition to Williamsburg, has independently run chapters in Crown Heights, Flatbush, and Borough Park – all Brooklyn enclaves densely populated by religious Jews.

Some people see them as a model for helping curb urban crime, though others fault them for clashing with outside groups – and even among themselves.•••

Shomrim is not your typical neighborhood watch. For starters, the groups have a 24-hour hot line and dispatcher, their own marked vehicles, and a track record for dealing with everything from assault and battery to domestic violence.

“Everything that happens in the world happens here,” says Yossi Pollack, a senior Shomrim member, as we drive through the streets of Williamsburg peering down alleyways. “Our telephone number is just like 911 – they call us for everything.”

It raises the question: In a city like New York, with one of the largest and most respected police forces in the world, why not just call the cops directly when a problem arises?

“A lot of people in the community are a little apprehensive of the police,” says Binyomin Lifshitz, who, along with fellow Shomrim member Gadi Hershkop, took me on a separate ride-along in Crown Heights. “They don’t want to interact with the police unless they absolutely have to.”

And when that happens, adds Mr. Hershkop, “Shomrim is like the liaison between the community and the police.”

The members of these Jewish enclaves feel more comfortable dealing with their own, both for language (Hebrew and Yiddish are prevalent) and cultural reasons. Furthermore, many are descendants of Eastern European and Russian shtetls, where, more often than not, it was the authorities who were behind their persecution.

Like the traditional dress, language, and customs sustained in these communities for centuries, apprehensions of law enforcement endure, too.

Community leaders also worry about the police getting involved and locking up someone who might not deserve it. When it comes to Jew-on-Jew crime, Crown Heights Shomrim will always consult a rabbi before involving the police.

“It’s been for centuries that Jews settle matters internally,” says Mr. Lifshitz.Yet the main focus of Shomrim seems to be protecting Jews from non-Jews. Williamsburg’s patrol, in fact, was started in 1977 by Rabbi Moshe Hoffman because he was tired of seeing fellow Jews fall victim to violent muggings.

But checking crime can be a delicate undertaking, particularly in Crown Heights, a community rife with racial tension. After all, Crown Heights lends its name to the infamous riots that occurred here in August 1991, when, for three days, blacks and Jews clashed over the death of a young African-American boy who was struck by an automobile driven by a Jew. The neighborhood, it seems, has yet to fully recover.

As Hershkop drives the minivan, Lifshitz points out where two Jews were recently beaten by a group of black youths. And last spring, after Andrew Charles, a young black man, was attacked by, according to police, two Jewish men with mace and a nightstick, activists connected with the Rev. Al Sharpton came and, as Lifshitz puts it, “riled things up.”

“Things got a little tense,” he says. “They were marching the streets of Crown Heights for ‘justice.’ We even took [our marked cars] off the street because we felt they were countereffective.”

Differences between the two communities linger. Richard Green, chief executive of the Crown Heights Youth Collective, says young black men are often profiled by the patrols as criminals. While he admits there have been improvements, Mr. Green thinks the patrols could benefit from more supervision by police and a better understanding of the black community.

For the most part, though, Green and other outsiders believe the patrols to be beneficial. Letitia James, the city council member who serves Crown Heights, says they “provide a service not only to the Jewish community, but also to the black community.”

That’s one test of a patrol’s effectiveness: Does it serve everyone in the area or just one religious or ethnic group?

“Citizens should be responsible for preserving safety and order in their own neighborhoods,” says Peter Moskos, a criminologist at John Jay College of Criminal Justice in New York. “But the question to ask is if Shomrim fights against all crime they see or just against crime done to their people. If it’s the latter ... then they’re more like a private security agency.”

While the Jewish patrols have had the occasional flare-up with outside groups, they also sometimes feud among themselves.

“To be blunt, we have a rival patrol, and they’re not well-disciplined,” says Hershkop, referring to Shmira, whose members also operate in Crown Heights and who can easily be mistaken for Shomrim.

A local grand jury has indicted Yitzhak Shuchat, who news reports have identified as a Shmira member, for various assault and hate-crime charges in relation to the Charles incident.“Some people compare us to the Bloods and the Crips. We try not to mix, and stay focused on the positive and the good,” Hershkop says.

Shmira member Yossi Stern calls the Charles case simply an “altercation between two people.” He denies Shmira was involved or uses heavy-handed tactics. He says Shmira has taken training with the NYPD and is the “official” security patrol for the Crown Heights Jewish community.

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With Hershkop piloting the minivan down Eastern Parkway, Lifshitz points to an intersection and recalls an incident from five years back, which, he says, illustrates the Shomrim’s reputation. Lifshitz was just 17 then, a newly minted Shomrim member. He was walking alone at night, on his way home from a wedding.

As he tells it, a black youth approached him and asked for the time. Lifshitz says he could see four other teens watching from across the street – and knew he was about to get jumped.

“No, I don’t have the time,” Lifshitz told him.

“You got a dollar?” the boy asked.

“No, I don’t got a dollar,” Lifshitz shot back.

“Give me a dollar!” the boy demanded, and suddenly Lifshitz was surrounded. He pulled his two-way radio from beneath his coat and issued a distress code. “10-13, 10-13,” he called. “Corner of Eastern Parkway and New York Avenue.”